Week 4: Problems and Exercises

5. Consider the E-R diagram in Figure 7-20. Based on this E-R diagram, answer the following questions:
a. According do E-R diagram Figure 7-20 the degree shows many to many which indicates there are several projects with several employees working on them.
b. The degree of the Used on shows “many” (maximum cardinality) coming from Tool and “minimum” (cardinality of zero) to Task.
c. There is one associative entity that appear in this diagram: Work on
d. How else could the attribute Skill be modeled?
e. There are no attributes that can be assigned to Work on as it is not an entity. We represent an attribute by placing its name inside the rectangle that represents the associated entity
f. Yes, Tool could be modeled as an associative entity because there could be many tools that are needed for the project that the team is working on.

16. CRITERIA | ALTERNATIVE A | ALTERNATIVE B | ALTERNATIVE C | Requirements | | | | 1. Easy to use (Fast) | Off the shelf Product | Off the shelf (fully customized) | Fully customized | 2. Linked to each other | Yes | Yes | Yes | 3. Point-of-sale component | Yes | Yes | Yes | | | | | Constraints | | | | 1. Cost to software | 10,000.00 | 20,000.00 | 25,000.00 | 2. Cost of hardware | 20,000.00 | 40,000.00 | 40,000.00 | 3. Time to operation | Two months | Three months | Four months | 4. Ease of training | One week of training | Two weeks of training | One week of training |

For Alternative A, you would fore go all the customization of "off-the-shelf" software, and that may not give you all the functions desired for reports and the particular business. To get a fully customerized it would take a bit longer than the time allowed and cost a bit more than the budget allows. If you pick Alternative B, you would get customization and be within budget and expected time